Hi there,
I didn't take Vicodin (we don't have that over here) but was taking Voltarol and co-codamol (sophodol) and about five weeks worth of different antibiotics following my tonsillectomy six weeks ago. Then when the Voltarol ran out I was on 400mg Ibuprofen with my sophodol. I too suffered from similar symptoms to you, diaorrhea, headaches and felt generally achy all over like I was permanently coming down with something! I thought that my stomach cramps and diaorrhea were side effects of the antibiotics as I had already weaned myself off of the painkillers by then. But, it could be withdrawal symptoms, especially when you have been taking it for weeks. I wasn't sleeping well either but, have been 'drug' free for a couple of weeks now and feel so much better. I still have a funny feeling in my throat on one side and am still tired but I am sleeping better, no headaches (apart from the odd one that the kids give me!) and no achy feeling. I actually felt well enough to go back to the gym last night - then I ached!!
You must remember that you have had surgery too so all the feelings that you are experiencing are normal. I was told that the older you are the longer it takes for you to recover from tonsillectomy. I got very depressed and the more down i got the worse I felt. Your feelings will improve but it does take time. I am now feeling around 80-85% better six weeks on.
Take care
Babe xx